There’s nothing quite as inviting as a crystal clear swimming pool on a hot summer’s day. But, the invitation gets a whole lot less tempting the minute your pool turns green. It’s every pool owner’s worst nightmare: a blue pool gone green! Fortunately, you don’t have to fill it with cement just yet, as it’s fairly simple to fix.


Why is my pool green?


The short answer is simple: your swimming pool is most likely green because of algae. If it’s still only slightly green, the algae growth has just begun. If it’s dark green, with patches of green growth on the surfaces of the pool, such as the steps, it’s a little closer to becoming a fish pond. But, all is certainly not lost. Algae are aquatic organisms which use photosynthesis to grow. Their spores are constantly finding a way into our swimming pools, such as via the wind or rain, and these multiply prolifically given the right conditions. If your pool water is imbalanced, lacking in sanitiser, or has poor circulation and filtration, algae will be itching to climb in and get a grip.


How do I turn my pool blue again?


Grab a brush and start scrubbing. You might want to replace your usual pool brush with a stiff-bristled or metal brush, as algae tends to be stubborn. Your pool skimmer net will also come in handy, for removing any floating algae and other organic matter. Test your pool water. Take note of the pH, total alkalinity and chlorine levels. Remember, the pH in your swimming pool should be between 7.2 and 7.6, the total alkalinity between 80 to 150 parts per million and the free chlorine between 1 and 3 parts per million. Then, shock, shock, shock! Buy a pool shock, high in chlorine, and dump it into the water. The chlorine is just what your green pool needs to get sanitiser levels back to normal. If your pool closely resembles a swamp, you may need to shock it three or even four times.

Filter your pool, sit back and wait – blue waters will be returning to a pool near you in a matter of days. As you run your pump through a course, you’ll also need to clean your filter as it collects algae. Finally, retest your pool water and make sure that it is balanced. To prevent walks down this particular memory lane, maintain your sanitiser levels and top these up regularly.


What if my swimming pool is green and it’s not algae?


To make matters slightly more complicated, sometimes it is not simply a matter of algae turning your pool green. If your swimming pool is tinted green yet unclouded, it is likely a result of dissolved metals in the water. To clear up your pool water, simply add a metal remover and then readjust the pH and total alkalinity. If your swimming pool is luminous green, it could be overstabilised if it also has high chlorine and stabiliser levels. In this case, stabiliser has been overused and it may require draining some of your pool if the stabiliser level is over 100 parts per million. Be sure that your stabiliser level is between 40 and 80 parts per million and retest your pH, shocking your pool if necessary.


What if my swimming pool is green and I don’t know why?


Green pools can be a little scary, but not for the experts. If you are unsure why your swimming pool has turned green or it still doesn’t clear up after treatment, get in touch with us for a pool cleaning service you can trust.